A series of fluorescent and phosphorescent probes for the investigation of micellar and biomolecular structure have been designed The quenching of the photoluminescence of these probes is the pertinent measurement that is made. A theoretical model for translating the quenching data into structural and dynamic parameters of micelles and biomolecules and associated probe molecules has been derived. From quenching data the following parameters have been evaluated; aggregation numbers, partitioning coefficients of probes, entrance and exit rates of the probe into and out of the aggregate. A method for measuring microviscosities of micelles and biomolecules has been devised. The formation of intramolecular excimers is the key measurement in this method. The ratio of excimer/monomer emission has been correlated with microviscosity. The dynamics of entrance and exit of oxygen molecules into and out of micelles have been investigated by fluorescence quenching experiments. The partitioning of oxygen in a micelle and aqueous environment has also been established by this method, and oxygen is found to be much more soluble in a micellar than in an aqueous environment.